Dominic Sorresso

I've been playing w the Inj. Bias for the last several months and the results have really been enlightening and very good. The motor runs smoother than it ever has, and the exhaust drone at low rpm everyone complains about has been seriously dampened making the car sooo much nicer to cruise in at 70mph. The Z06 NPP actuators also help especially considering that I do not have a resonator. Just headers, Xpipe, and DynoMax mufflers.
Anyway, besides the good stuff, I have also seen that the motor will go into and out of closed loop for what appears to be no reason. Nothing changes in the way the motor is running. If I wasn't logging, I would never know it. My WB doesn't change at all. I'm attaching a snip of a log showing the motor slipping into O/L. From what I can see, the O2 V stays very constant during this time. Not sure if this is the cause or what is bringing on O/L. It appears that the O2 sensor is not transitioning. Don't look at the Left O2 Xcounts because I have gms/sec. showing up there instead of sensor transitions.
Is it possible I may need to bump the Prop Gain a bit to induce Xcounts. This really does not happen at idle but rather when I am cruising and the throttle is relatively steady or trailing throttle. When it goes into O/L , if I nudge the throttle it jumps back into C/L.

RBob

iTrader: (1)

If the O2 sensor isn't active the ECM will typically drop out of closed loop. Although this usually sets a malfunction code 13.

What is the INT doing during this time? If the proportional gains are too low I'll see the INT going up & down to create cross counts.

RBob.

Dominic Sorresso

RBob,

Uploaded zip file w .txt file of the log. I see the INT "ranging" but you would know better than I. The motor note is very steady at cruise. I have also attached a pic of the Prop Gains as they are v Stock.

RBob

iTrader: (1)

Couple of graphs, the upper is the two O2 sensor readings in voltage. The lower is the two INT values. Left O2 sensor input is bad. With the problems you have been having with that sensor I'd say that the ECM has an issue.

Looking at the right values we see that there isn't enough proportional gains. The INT is slowly rising and falling with the O2 reading trailing it.

RBob.

Dominic Sorresso

Very interesting RBob and thank you for the analysis. The issue I was having previously however was w the Right O2 where the signal was dropping to 0. I made a new extension harness for it and that issue seems to have been eliminated. So, IOW, THE "LAZINESS" of the left side O2 is what is causing the ECM to go O/L? I have a spare ECM, so I may switch it and do another log.
As for the prop gain, would you suggest a global increase, and if so how much to start? Or do I do it by O2 error or airflow? I have reduced the prop gains regarding airflow and error. I may also see if I can find some AC O2 sensors to replace these Bosch ones.

RBob

iTrader: (1)

With it having been the right O2, then the ECM likely isn't the issue. Most likely a bad sensor.

As for prop gains, I only checked that one area of RPM/airflow. Check other areas of higher airflow to see which way to go.

RBob.

Dominic Sorresso

RBob,

Bumped the PropG a couple of clicks. This appears to have significantly cut down on the Open/Closed loop cycling I was seeing. Looking at the latest log, I can still see the INT oscillating still but mainly at 64gps. Idle was really pretty nice and a bit smoother than previous.
Also ordered a pair of AFS-74 O2 sensors to replace the Bosch.

RBob

iTrader: (1)

Sounds like they are now close enough to tweak via the airflow table.

RBob.

Dominic Sorresso

I used both PG tables, gms and O2 error. 02 error increased by 3%.

RBob

iTrader: (1)

That's fine, no issues with using both tables for global changes. Can now use just the gm/sec table to tweak it in via the engine's airflow.

RBob.

Dominic Sorresso

So RBob, you think I should leave the O2 Error table alone?

Dominic Sorresso

AC AFS 74 O2s installed. This was part of the most recent "upgrade" w larger aluminum radiator. Car was up on jackstands making O2 sensor swap easy, relatively.

Dominic Sorresso

Got an opportunity to datalog w new AC O2s installed. They seemed to tell a bit of a different story re: BLMs. Motor appeared to be running leaner than I had observed before.
Could that also be a result of running more IAC counts? One other observation is that the motor was not dropping in and out of C/L. Once there, it stayed in C/L. Going to check the
O2 transitions to see if I have enough Prop Gain.

Dominic Sorresso

Based on the datalog today, C/L is very solid along w Learn. I may need to add a touch of prop gain in the mid section of the airflow table, but seems like just a touch.

RBob

iTrader: (1)

Sounds like it's working out with the new O2's.

RBob.

Dominic Sorresso

RBob,

Yeah looks like the ACs are doing their work. Perhaps increasing the PropG also has helped thanks to you. One difference is that the BLMs now appear to be further apart than before particularly at idle. Just gave the exhaust another crank down on the clamps in case. Also, got the A/C re-charged and now have had to take that into account on the tune. Found some new areas in the VE table causing a nasty lean surge.